Case Study of Composite Chassis Manufacturing Process Using Low Temperature Molds Tempered with Gradual Heat Annealing Process

This case study describes a manufacturing process of composite chassis also known as monocoque. The structure is made using carbon fibre reinforced polymers (CFRP) which are manufactured in out-of-autoclave (OOA) process from pre-impregnated carbon fabrics and aluminium alloy honeycomb core. Since the material cost is high the aim of the project was to reduce the cost of manufacturing process i.e. cost of models and moulds. Therefore, instead of high-temp models and moulds a cheaper alternative was used. It consisted of Styrofoam models made using polyurethane (PU) paste and moulds made from CFRP using wet layup process which were cured at room temperature. Such moulds had to be adapted to withstand high temperatures during pre-preg cure. This was done with gradual heat annealing process which increased the maximum service temperature from 45C to 90C. This was enough for the low-temp cure of pre-preg material, but it might be possible to increase the temperature even further. As a result, the cost of manufacturing process had been reduced by 50%.